Test Text1 plain Hey, guys, back at 7:41 with "Gma" investigators. Before you fire up the grill, there are very real dangers. Grilling can be safe, but thousands are hurt every year. You have to follow the rules, and here is Alex Perez. Reporter: Summer sizzles. Family cookouts are here. Look how quickly the flames are moving. Reporter: But a few mistakes and summer time fun can turn dangerous. Every year, gas and charcoal grills cause 86,000 house fires and injure 7,000 people. Hannah storm is one of them. While making dinner in December of 2012, she started up the grill, went inside and returned to find no flame. Without turning the gas off, she relit the grill. Huge fire ball exploded. All of this was burning, on fire here. Reporter: The explosion so intense, she suffered severe burns on her face, chest and hands. Pro pain is a monster, okay? You have to respect it. You have to read the grill instructions. Who does that? Reporter: To show you how to protect your family, "Gma" investigators teamed up with the laboratories. Gas or propane. This is a big hazard? Could be if you don't do it right. Reporter: Check hoses for gas leaks. Best way, soap and water on the connection to the valve. There's a leak. Reporter: Keep the lid open when lighting the grill. We intentionally closed the lid and turned on the gas. A ticking time bomb. It could be. Reporter: And we ignited the grill. Tch in slow motion, you see the gas build up, explode when we hit the ignition switch. Singing the hair on the mannequin. And the grill should be ten feet away from the house. We put this too close to the demonstration house. After just a few minutes, the flames flare up,ing fi igniting the hanging plants. We have to move now, it's too hot. Reporter: Not long after that, the home in flames. A fire fighter standing by to ex-ting wex ti ex-ting wish it. For "Good morning America," Alex Perez, Chicago. It's useful especially on

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Learn important safety tips on how to avoid accidental injury when grilling.

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